/Engine/Plugins/Online/OnlineSubsystem/Source/Public/Interfaces/OnlineChatInterface.h
Get cached list of rooms that have been joined
void GetJoinedRooms ( const [FUniqueNetId](API\Runtime\CoreOnline\Online\FUniqueNetId) & UserId, [TArray](API\Runtime\Core\Containers\TArray)< [FChatRoomId](API\Plugins\OnlineSubsystem\Interfaces\FChatRoomId) > & OutRooms )